Organic polymers undergo degradation in the presence of light and heat, and this degradation is accelerated when the intensity of the light and the temperature are both high. The light which causes the degradation ranges in wavelength from the infrared through the visible into the ultraviolet, with the shorter wavelengths, i.e., the ultraviolet, causing the greatest degradation. This problem is especially severe in luminaires, where both heat and light are intense, but it is troublesome in many other applications where polymers are exposed to natural or artificial light and heat.
Stabilizers against the degrading effects of light are known, and include polymeric hindered amines and melamines with highly aromatic substitution. Such stabilizers are expensive and difficult to prepare, and they fail to offer effective protection against the effects of heat. For example, poly((6-(1,1,3,3-tetramethylbutyl)amino)-s-triazine-2,4-diyl)(((2,2,6,6-te tramethyl-4-piperidyl)imino)hexamethylene((2,2,6,6-tetramethyl-4-piperidyl) imino)), a commonly used hindered-amine light stabilizer sold under the trademark Chimasorb 944 LD, significantly degrades the thermal stability of poly(vinyl chloride).